I saw this sign at the entrance to the woods the other day, and when I got close to read it, it said something like "don't come over here, we're trying to grow wildflowers in this spot."
And today I saw another sign, which is far easier to read:
By the way, Americans might find this custom quaint: when British people leave notices out for people saying things like "Please don't park here" or "Please pick up after your dog" they always preface it with the words "Polite Notice".
Such a contrast to the "Recycle or Die!" sign I saw when I first visited Madison Wisconsin.